Traumatic dental injury refers to damage to the tooth, pulp and periodontal tissue caused by external forces, especially blows or impacts. Children are more active, strenuous sports or play are often prone to collision or fall, and sometimes due to other accidents, are easy to cause dental trauma. The front teeth are in the more prominent part of the face, and the lack of facial skin and muscle protection, therefore, in pediatric dentistry clinical anterior dental trauma is the most common. The trauma to the baby teeth mostly occurs in children aged 1-2 years old, accounting for about 1/2 of the trauma to the baby teeth, during which children start to learn to walk and easily fall and cause dental trauma. In recent years, some scholars have reported an increasing trend of molar trauma in children aged 2-4 years, and pointed out that it is related to the change of living environment. Young permanent dental trauma occurs mostly in children aged 7-9 years old, and the incidence of dental trauma decreases with increasing age. Because kindergarten children are mostly 2-7 years old and some of the older children have erupted their maxillary anterior teeth, trauma to both the milk and permanent teeth in kindergarten should be taken seriously. When dental trauma occurs in children, the whole body of the child should be examined first to exclude the possibility of cranio-cerebral injury. Then, the child should be questioned in detail about the injury. If cranio-cerebral trauma is found, even if it is suspicious, the child should be promptly examined in a general hospital and then dental treatment should be carried out after the consultation and treatment is over. 1, young permanent tooth trauma Young permanent tooth trauma is characterized by thin dentin, large pulp cavity and high pulp angle, so it is easy to expose the pulp. In addition, since the root of young permanent teeth is not yet developed, trauma and root canal treatment can easily affect apical atresia. Moreover, since the tooth is in the process of eruption, it is difficult to fill and restore the crown. Considering the above characteristics, rapid and appropriate treatment should be given to young permanent teeth after trauma to ensure normal development of permanent teeth. Young permanent teeth with undeveloped roots are prone to tooth dislocation when they are subjected to external forces. For completely dislocated teeth, the health care practitioner should master the emergency treatment: rinse the dislocated tooth with saline or tap water, place it in milk or saline for preservation, or place it under the child’s tongue and immediately go to the hospital for reimplantation. If there are contaminants on the root surface, do not scratch or scrub the root surface with instruments, and do not wrap the affected tooth with hands or paper to the hospital, because this will damage the living periodontal tissue and affect periodontal healing. In conclusion, trauma to young permanent teeth must be taken seriously, handled quickly, promptly to the hospital, and require long-term observation and regular review, so as to minimize the damage. 2, trauma to milk teeth Trauma to milk teeth mostly occurs in the upper front teeth, especially the upper central incisor, mostly caused by falls. Since there is a developing permanent tooth embryo at the root end of the baby tooth, trauma itself or improper treatment can cause damage to the permanent tooth embryo. A mild injury can cause enamel underdevelopment of the permanent tooth, while a serious injury can lead to a bent deformity of the permanent tooth crown and root, or even stop the development. Therefore, trauma to the milk teeth should also be taken seriously.